In construction, road building and other industries, machine systems are often used to controllably place material to be used as a supporting substrate. In the context of paving roads, parking lots, etc., a paving machine is typically used to deposit and preliminarily compact a paving material which is later treated via one or more compacting machines to render a relatively hard, smooth traffic-bearing surface. A conventional paving machine includes a material storage hopper, a conveyor to transport material within the paving machine and a material placement mechanism such as a screed apparatus which controls a thickness and width of paving material deposited onto a work surface. For most jobs, the storage capacity of the hopper is insufficient to store all the paving material which will be placed by the paving machine. It is thus typically necessary to resupply the paving machine with material to be deposited such as asphalt, concrete or aggregate materials, periodically or continuously during operation.
To this end, many paving systems include supply machines which deposit material ahead of a paving machine on a surface to be paved. The paving machine may be equipped with or accompanied by a mechanism for loading the hopper with the material placed on the surface. One known system utilizes a mechanism known as a windrow elevator to elevate paving material deposited onto the surface in a windrow into the hopper of the paving machine. In other strategies, a machine known generally in the art as a material transfer vehicle will pick up loads of paving material deposited at a work site and shuttle the paving material to one or more paving machines, more or less on an as-needed basis.
It is generally desirable to avoid interruptions in paving material supply, but also generally desirable to avoid oversupplying paving material. In other words, to operate a paving system as efficiently as possible it is generally desirable to control the rate of supplying/resupplying paving material to a paving machine to avoid situations where paving progress stops because the machine runs out of material, and also to avoid situations where excess material is supplied. If excess material is supplied, then the storage capacity of the paving machine hopper may be exceeded. It may then be necessary to manually shovel excess material out of the paving machine hopper or remove material from a windrow to avoid overwhelming the paving machine and causing system down time. Likewise, it is typically desirable to avoid idling the paving machine by inadvertently halting material supply.
For the reasons explained above, it will be readily apparent that providing a consistent and accurate supply of paving material to a paving machine can be critical if paving is to progress at a theoretical optimum efficiency. In many instances, a paving machine operator or other personnel will be responsible for ordering the resupply of paving material to the paving machine. Paving material may be ordered based on visual observation of the material supply available, experience and, to a large extent, guesswork. In one conventional system, workers on the ground manually control depositing of paving material onto a work surface ahead of the paving machine. One problem with manual control strategies is that the personnel responsible for controlling a location and/or quantity of paving material deposited onto the work surface may not be capable of controlling the discharge amount or location of paving material with sufficient precision as to time, location or quantity to avoid oversupply or undersupply. Moreover, personnel responsible for controlling delivery and deposition of paving material on the work surface may not be privy to the actual volume of material needed, much less aberrations or changes in the rate of paving of the paving machine or the amount of material the paving machine is putting down. For example, during operation a paving machine may change paving width and paving thickness regularly. While an observer may make basic assumptions as to the rate at which paving material is being placed by the paving machine or a quantity of material required to pave a particular stretch of road, for instance, visual observation and experience are often insufficient to accurately determine how much material should be laid down ahead of a paving machine for pick-up. These and other confounding factors tend to compromise the efforts of even skilled site managers and machine operators to run a paving system at optimum efficiency.
United States Patent Application No. 2006/0002762 to Crampton is directed to a method and apparatus for spreading aggregate and road building materials onto a surface in relation to speed of a spreading machine. Crampton teaches a spreader assembly for controlled delivery of aggregate materials from a hopper to a surface. Crampton recognizes that some aspects of road quality can relate to depositing a measured and/or uniform amount of material. However, while Crampton may be suited to a certain type of machine system or paving strategy, Crampton is not concerned with nor applicable to supplying material for subsequent placement with a paving machine. Moreover, Crampton does not recognize the need or advantages to communicating certain types of data among machines of a complex system.